Moving flange for passenger conveyors

ABSTRACT

Passenger conveyor ( 2 ) including an endless conveyor band ( 6 ) comprised of a plurality of tread elements ( 4 ) connected to and driven by a drive chain ( 8 ) at each lateral edge thereof, a moving flange moving in use together with the conveyor band ( 6 ), the moving flange being comprised of a plurality of discs ( 16 ) attached to the tread elements ( 4 ) and a plurality of bridges ( 18 ) each attached alternating between two consecutive discs ( 16 ), wherein a groove and tongue ( 70 ) engagement is provided between bridge ( 18 ) and disc ( 16 ), characterised in that an insert ( 64 ) made of a plastic material is provided between bridge ( 18 ) and disc ( 16 ).

The present invention relates to passenger conveyors including anendless conveyor band comprised of a plurality of tread elementconnected to and driven by a drive chain at each lateral edge thereof, amoving flange moving in use together with the conveyor band, the movingflange being comprised of a plurality of discs attached to the treadelements and the plurality of bridges each attached between twoconsecutive discs.

Such a passenger conveyor is known for example from WO 02/44072 A1.Escalators and moving walkways are typical examples of such passengerconveyors. An escalator usually contains a series of movableinterconnected tread elements that are referred to as “steps” and drivenaround upper and lower chain reversing wheels or other reversalconstructions by a driving motor. These interconnected steps arereferred to as a passenger conveyor band or step band. Similarly, movingwalkways contain several interconnected pallets that are also drivensuch that they revolve around two chain reversal constructions. Inmoving walkways of this type, the passenger conveyor band is usuallyreferred to as a pallet band.

With the passenger conveyor of WO 02/44072 a moving flange is providedat each lateral edge of the tread element extending upwards from thetread surface so as to avoid any relative movement between the treadsurface of the tread element and a fixed skirt laterally adjacentthereto. Such flange excludes any entrapment in the gap between themoving tread elements and the fixed skirt which is possible inconstructions without such moving flange or moving skirt. Particularly,the moving flange is formed of an alternating series of first flangeparts connected to the tread elements which are referred to as “discs”and second flange part which are arranged between subsequent discs andwhich are referred to as “bridges”. The discs and bridges are arrangedconsecutive next to each other so that they form a substantiallycontinuous moving flange. A tight gap is provided between the discs andbridges in order to allow relative movement there between, particularlywith escalators. An inner decking covers the upper edge of the movingflange. The inner decking typically extends from the balustradedownwards a certain distance beyond the upper edge of the moving flange.

While the moving flange greatly enhances the safety of passengerconveyors as compared to conventional designs, it poses new problems forthe engineers in this field. One of the problems which arise in thistype of conveyors is to provide a moving flange which is thin and stableand which is designed for the lifetime of the conveyor. For example, theGerman TÜV tests the moving flange by applying a force of 1.500 Newtonperpendicular to the moving flange. With such force, the deviation ofthe moving flange must be less than 4 mm with total recovery once theforce is no longer present. In order to secure integrity of the exposedsurface as formed by the discs and the bridges, it has already beensuggested to provide a groove and tongue engagement between the discsand the bridges (see WO 02/44071 A1). Such a groove and tongueengagement can be of a relatively loose fit with sufficient clearancethere between so that there is practically no or little contact onlybetween the tongue and the groove surfaces. Nevertheless, in order tosecure the required clearance between the groove and tongue machining ofthe surfaces of at least one of the groove and tongue is required. Suchmachining is, however, substantially adding to the cost particularlywith parts like bridges, which can generally be used directly after thedie casting manufacturing step or after uncomplicated machining only.

It is therefore the object of the present invention to reduce themanufacturing cost for the flange parts while providing a good qualitysurface at the groove and tongue engagement.

According to the present invention this object is achieved by providingan insert made from a plastic material at the engagement surface betweenbridge and disc. It is known that good quality surfaces can be producedby plastic injection moulding at reasonable cost. It has turned outthat, while this insert is an additional part and, providing such aninsert can substantially reduce manufacturing cost. Various plasticmaterial can be used. Plastic materials with good sliding capabilitiesrelative to aluminium are preferred, since the flange parts aretypically made from die cast aluminium. Particularly preferred areplastics like DELRIN 500AL NC (from the company Du Pont) andalternatively materials including a chemical lubricant and/or beingKevlar modified like DELRIN 500CL NC or DELRIN 500KM NC.

Preferably, the insert is clipsed or snapped onto the disc or bridge.Alternatively, the insert can be injection moulded directly onto theperspective part. It is particularly preferred that the tongue islocated on the bridge. It is also preferred to attach the insert ontothe tongue.

Preferably, the clip or snap connection includes snap recesses which areprovided in the tongue of the bridge wherein the mouth of such recessesis directed essentially radial with respect to the circular shape of thetongue.

Thus the snap connection can provide a positive fixture of the insert inthe circumferential direction, i.e. the direction of relative movementbetween disc and bridge. It is to be noted that the direction of thesnap recesses can deviate to some extent from the precise radialdirection. It is sufficient if the snap connection can provide apositive fixation in the circumferential direction. Practically, aplurality of snap recesses is provided for each insert with one of thecentral recesses being oriented relatively precisely in the radialdirection and the further recesses being oriented essentially parallelto this central recess. Such a construction allows easy mounting of theinsert in the same snap direction. This attachment method can also beapplied if the tongue is provided at the discs.

It may also be preferred to have an insert on both the bridge and thedisc. This is particularly preferred if a good surface quality isrequired also with the engagement surface of the respectively othercomponent.

Another problem relates to the attachment of the bridges. While thediscs are securely attached to the tread elements, it is a difficulttask to safely secure the moving bridges as well. Particularly, themoving bridges have to be attached to any moving part so that it isimpossible for the bridges to get lost from the moving flange. In case abridge gets lost, an “opening” is travelling along with the movingflange with the high risk that any objects are entrapped at the exitlanding where the opening “disappears”. Therefore, a reliable and securemount of the bridges is mandatory.

On the other hand, as described in WO 02/44072, easy removal of theindividual tread element for maintenance purposes is also of greatconcern. The removal of the tread elements requires the disassembly ofthe inner decking, the dismounting of the bridges in contact with therespective step and subsequent removal of the step as described in thisdocument. These two objects, i.e. safe securement and easy disassembly,are somewhat in contradiction to each other.

The engineers of the applicant have contemplated different solutions forthe bridge mounting. One solution was to mount the bridge by way of athreaded bolt directly to a chain link. However, threads in the chainlink which is die cast from aluminium material, have a limited lifetimeonly. This reduced lifetime is a problem, as one can expect dismountingof a bridge several times during the conveyor's lifetime. On the otherhand, the bolt is a separate component which can get lost duringassembly and disassembly, fall into the interior of the conveyor andmight cause harm therein. Moreover, there is a limited space availableat this location resulting in that the bolt has to be positioned veryclosely to the inner surface of the bridge. However, in order to providethe required structural stiffness of the bridge part, stiffening ribsare provided at the inner surface thereof. The bolt mount requires tohave a bore through such stiffening ribs at the central portion thereofwhich tends to weaken the bridge. Moreover, a bolt has to be tightenedwith a certain tightening moment. This increases the risk for incorrectassembly.

Thus it was the object of the engineers to provide a reliable, fail safeattachment mechanism for a bridge without any loose parts and which canbe mounted and dismounted with simple tools.

This object is achieved by a passenger conveyor as described abovewherein at least one bridge is attached to the drive chain by means of apin and socket connection and that a resilient locking element isarranged so as to bias in use the bridge against the chain.

Preferably all the bridges are attached to the drive chain in thismanner. The resilient locking element provides for a clearance-freeattachment of the bridge. Moreover, this element can be made so as toprovide a clearly audible noise once the bridge safely snaps in. Thisavoids any incorrect mount by the service technicians. The resilientlocking element can be constructed so as to be operable by a simpletool, for example a screw driver, etc. Moreover, no loose parts arerequired.

Preferably, the pin is attached to a chain link, while the socket isattached to the bridge. With such a construction, the bridge can easilybe slid onto the pin even without any tools. Preferably the pin isthreaded into the chain link. This is a relatively easy mount. The chainlink is to be machined very intensively anyhow after die casting, as ithas to keep close tolerances, thus machining a thread bore is notsubstantially increasing costs and machining time. A “one-time” threadconnection is a relatively secure connection for the link. Moreover, itis possible to further secure this thread connection by way of adhesive,since it is not necessary to untighten the pin subsequently. It is alsopossible to attach the pin by any different way to the chain link, forexample by way of a press fit, adhesive only, etc. Preferably, thesocket is an integral part of the bridge. For example, the socket may bea simple bore in the bridge. It is preferred to have a bore manufacturedafter the die casting process, to just having an opening formed by diecasting, in order to have close tolerances between the pin and thesocket bore. Alternatively, the socket may be formed separately andattached to the bridge.

Preferably, the resilient locking element is a wire locking spring. Thespring can be fixed to the bridge and engaging an engagement surface ofthe pin. The engagement surface of the pin preferably is a groove whichis formed in the pin. The upper flange or wall of the groove may serveas the engagement surface. The wire locking spring is preferably madefrom stainless steel in order to avoid any corrosion, etc. Preferablythe wire locking spring is resiliently clipsed or snapped on to thebridge. Preferably, the wire locking spring is W-shaped. Recesses can beprovided on the bridge for engagement with the spring. Thus, the springcan easily be snapped on the bridge during manufacture. Preferably, thesnap-on direction of the spring onto the bridge is substantiallyperpendicular to the snap on direction between pin and socket. Thus, asecure engagement of spring and bridge in the locking direction of pinand socket can be secured.

Preferably, the top of the pin is tapered. The taper of the top of thepin allows to slide the bridge onto the pin without requiring any tool.The tapering surface urges the spring out of its position against thebias of the spring. Once the spring is moved beyond the engagementsurface of the pin, the spring moves back towards its original positionand locks the bridge in place, resulting in a clear audible noisesignalling to the service technician that the bridge has correctly beenmounted.

The invention an embodiments of the invention are described in greaterdetail below with reference to the figures, wherein

FIG. 1 shows a portion of a passenger conveyer according to the presentinvention;

FIG. 2 is a view of a bridge which is attached to a chain link inaccordance with the present invention;

FIG. 3 is a perspective view similar to that of FIG. 2.

FIG. 4 shows a pair of inserts according to the present invention;

FIG. 5 is a sectional view showing the snap detail;

FIG. 6 shows a bridge according to the present invention without aninsert attached thereto; and

FIG. 7 is a detailed view of the pin for the pin and socket connectionaccording to the present invention.

FIG. 1 shows an inventive passenger conveyer 2 with an endless passengerconveyer band 6 that is composed of several interconnected treadelements 4. The tread elements 4 are connected to drive chains 8 thatare respectively arranged laterally of the tread elements 4 and consistof a series of chain links 10. The chain links 10 are connected to oneanother at pivots 12. The passenger conveyer 2 is driven by a conveyerdrive, for example a linear drive, etc. The drive engages a toothing 14of the chain links 10.

In FIG. 1 the shown passenger conveyer 2 consists of an escalator. Onescalators, the passenger conveyer band 6 is referred to as a step band,and the tread elements 4 are referred to as steps. FIG. 1 mainly showsthe step band 6, the drive chain 8 and chain and step rollers 30 and 22,respectively. Thus, roller guide tracks, etc. are not shown in FIG. 1.One of the steps 4 is removed from the step band 6. For the particularconstruction which allows for easy removal of the step 4 from the stepband 6, reference is made to WO 02/44072 A1. The step 4 contains alateral flange element, i.e. disc 16 that moves together with the step3. The discs 16 are rigidly fastened on step 4, wherein a second type offlange element, i.e. bridge 18, is respectively arranged between twosucceeding discs 16. The bridges 18 bridge the interstice betweenconsecutive discs 16 and are connected to the drive chain 14 as detailedbelow. The bridges 18 may also be attached to any other structural partmoving together with the steps 4 and chain 8.

The discs 16 have a circular shape with the pivot or attachment point 12of step 4 being the center of the circle. Correspondingly, the bridges18 have correspondingly shaped circular edges. A groove and tongueengagement is provided at the contacting surfaces of the discs 16 andbridges 18 for maintaining the integrity of the exposed surfaces ofbridges 18 and discs 16. With such construction the bridges 18 areattached to the chain links 10 exactly in the middle between consecutivepivots 12.

The steps 4 are moved in a revolving fashion by the drive chains 8. Steprollers 22 arranged at arm 20 serve for controlling the position of thestepping surface 24 of the step 4. The step roller 22 is guided in aguideway or guide track (not shown). The guide track follows apredetermined curve for the step roller 22 such that the position ofeach tread element 4 is defined in a compulsory fashion. During suchmovement discs 16 and bridges 18 translate relative to each other in thetransitional areas and the reversal region.

As mentioned above, step 4 contains the stepping surface 24 and a stepfront side 26 that is also referred to as the “riser”. The individualchain links 10 of the drive chains 8 are connected at the pivots 12 bymeans of short axial bolts 28. Chain wheels 30 are rotatably arranged onthe outside of the axial bolts 28.

Two chain links 10 of the left and the right step chains 8 which areidentically arranged relative to the step 4 are rigidly connected to oneanother by means of a connecting axle 32. The connecting axle 32 doesnot protrude out or beyond the chain link 10. Each step 4 has a lateralholding device by means of which it is connected to a drive chain 8.Regarding the particular construction, reference is made to WO 02/44072A1. With such construction it is relatively easy to disassemble steps 4from the step band 6 even at locations remote from the region reversalat the upper and lower landings, respectively.

It is to be noted that while the present invention is being describedherein with respect to an escalator, it is also applicable in a movingwalkway.

FIGS. 2 and 3 show details of the chain link 10 and bridge 18.Particularly, FIG. 3 shows the exposed face 32 of the bridge 18, i.e.the face which can be seen by the passenger who is standing on the stepband 6. FIG. 2 shows the reverse side 34 of the bridge. Reinforcementribs 36 are arranged so as to provide the structural stiffness for thebridge 18.

Particularly, the bridge 18 is attached by means of a pin and socketconnection 38 to the chain link 10. The socket is essentially comprisedof a bore 40 in the interior of a cylindrical element 42 which is castintegrally with the bridge 18. A pin 44 is positioned in bore 40 andretained in position by way of a wire locking spring 54.

Reference is made to FIG. 7 which is a detailed view of the pin 44. Pin44 has a head portion 46 including a taper 48 and a reduced portion 50.The reduced portion 50 forms an engagement surface 52 for engagementwith the locking spring 54. The lower end 56 of the pin 44 is threaded.A lock nut 58 is provided at the threaded portion 56. The threadedportion 56 of the pin 44 is threaded into the protrusion 60 (see FIG. 3)on chain link 10.

The locking spring 54 has a substantially W-shaped form. It is snappedwith its lateral ends into the circular edges 62 of the bridge 18 in away that it is positively locked against movement in the direction ofpin 44 by engagement surfaces of the bridge.

For unlocking the bridge element 18 it is sufficient to bring a screwdriver in engagement with the locking spring 54 adjacent to the head 46of pin 44 and to advance the screw driver towards the chain link 10. Bydoing so, the taper of the screw driver moves the locking spring 54 outof engagement with the engagement surface 52. It is then easily possibleto lift the bridge 18 off. Vice versa for assembling the bridge 18 tothe chain link 10, pin 44 needs to be inserted in bore 40. By way ofpressing down the bridge 18, the locking spring 54 comes in contact withthe taper 48 of pin 44. In the course of further movement of bridge 18,the locking spring 54 slides behind the engagement surface 52 andsecures bridge 18 in position. In doing so, the resilient force of thespring pushes it heavily against the reduced portion 50 of pin 44resulting in a clearly audible noise which signals the correctattachment of bridge 18 to the service technician. The locking spring 54biases the bridge against the chain link 10.

In order to facilitate mounting of the bridge 18 to link 10, andmoreover in order to further bias the bridge 18 against the chain link10, it is preferred to have a resilient element (not shown) next to orinstead of the lock nut 58. The resilient element may be any type ofspring or can be made of a resilient material.

It is to be noted that as viewed from above downwards in the directionof pin 44, the reinforcement ribs 36 overlap pin 44 at least partially.As it is not necessary to turn or screw the pin with a tool, there is noneed for providing a bore or cut-out in the reinforcement ribs 36.

Fixed to the circular edges 62 of the bridge 18 is one insert 64 each.Particularly, the inserts 64, which are shown in more detail in FIG. 4,are of an essentially U-shaped cross section and comprise snap elements66 for engagement with correspondingly formed snap recesses 68 (see FIG.6) in the tongue 70 of a groove and tongue engagement between bridge 18and disc 16. The corresponding groove (not shown) is formed in the disc16. The tongue 70 is formed in circular shape along the circular edges62 of bridge 18.

Snap element 66 is shown in detail in FIG. 5. FIG. 5 is a sectional viewof the insert 64, particularly a section parallel to the two flanges ofthe U-shaped insert 64 through a snap element 66 and a web 72 which isconnecting the two flanges 74, 76 of the U. The snap element 66 connectsat location 78 to the web 72. The snap element 66 has a stem portion 80and a cylindrical portion 82. A drop-like through-opening 84 is providedin the snap element 66 in order to provide for a certain flexibilitythereof. Stem portion 80 and cylindrical portion 82 are integrallyformed with the web 72 and one of the flanges, i.e. flange 74 in FIG. 4.In the opposite flange 76 a cut-out 86 is provided around the snapelement 66. Thus, stem portion 80 and cylindrical portion 82 are notattached on this side. This construction further enhances flexibility ofsnap element 66.

The three snap elements 66 of insert 64 are arranged essentially inparallel to each other, i.e. the stem and cylindrical portions 80, 82respectively, of the individual snap means 66 protrude in parallel toeach other from web 72. Similarly, the snap recesses 68 are arrangedessentially in parallel to each other. This orientation of the snapelement 66 and snap recesses 68 facilitates assembly of the insert 64 tobridge 18. One may notice in FIG. 6 that each snap recess 68 has a mouth88. During snap-on, each snap element 66 is pressed through a mouth 88which provides an opening which is somewhat smaller than the outerdiameter of the cylindrical element 82. Due to flexibility of the snapelement 66 the snap element 66 can be moved through the mouth 88 intothe snap recess 68 and locks the insert 64 in position.

1-10. (canceled)
 11. Passenger conveyor including an endless conveyorband comprising: a plurality of tread elements connected to and drivenby a drive chain at each lateral edge thereof; a moving flange moving inuse together with the conveyor band, the moving flange including aplurality of discs attached to the tread elements; a plurality ofbridges each attached alternating between two consecutive discs, whereina groove and tongue engagement is provided between bridge and disc; andan insert made of a plastic material is provided between bridge anddisc.
 12. Passenger conveyor according to claim 11, wherein the insertis snapped onto the disc or bridge.
 13. Passenger conveyor according toclaim 11, wherein snap recesses are provided in the tongue of the bridgewherein the mouth of such recesses is directed essentially radial withrespect to the bridge.
 14. Passenger conveyor according to claim 11,wherein at least one bridge is attached to the drive chain by means of apin and socket connection and that a resilient locking element isarranged so as to bias in use the bridge against the chain. 15.Passenger conveyor according to claim 14, wherein the drive chain ismade up from a plurality of chain links hingedly connected to oneanother and the pin is attached to a chain link.
 16. Passenger conveyoraccording to claim 15, wherein the pin is threaded into the chain link.17. Passenger conveyor according to claim 14, wherein the socket is anintegral part of the bridge.
 18. Passenger conveyor according to claim14, wherein the resilient locking element is a wire locking spring fixedto the bridge and engaging an engagement surface on the pin. 19.Passenger conveyor according to claim 18, wherein the wire lockingspring is W-shaped and resiliently snapped onto the bridge. 20.Passenger conveyor according to claim 14, wherein a top of the pin istapered.